MARTI RPT-30 Transmitter (broadcast radio)

43 Pages·1993·1.682 MB·English

W A R N I N G

THIS EQUIPMENT MUST BE OPERATED WITH A 3-PRONG
GROUNDED OUTLET RECEPTACLE. FAILURE TO USE A
PROPERLY GROUNDED OUTLET MAY RESULT IN IMPRO-
PER OPERATION OR SAFETY HAZARD!

COPYRIGHT NOTICE
LIMITED WARRANTY
©1993 All Rights Reserved

Marti Electronics, Inc.
The Seller warrants that, at the time of shipment, the
4th printing, December 1993
products manufactured by the Seller are free from

defects in material and workmanship. The Seller's
No part of this manual may be reproduced, transmit-
obligation under this warranty is limited to replace-
ted, transcribed, stored in a retrieval system , or
ment or repair of such products which are returned to
translated into any language, natural or computer, in
Marti at its factory, transportation prepaid and
any form or by any means, without the prior written
properly insured, provided:
permission of Marti Electronics, Inc.
a. Notice of the claimed defect is given to Marti

within one (1) year [two (2) years for STL systems]
Artwork depicting circuitry in this manual is pro-
from date of original shipment and goods are re-
tected by copyright laws.
turned in accordance with Marti instructions.

b. Equipment, accessories, tubes and batteries not Information in this manual is subject to change
manufactured by Marti are subject to only such ad- without notice and does not represent a commitment
justments as Marti may obtain from the supplier on the part of Marti Electronics, Inc.
thereof.
Marti Electronics may make improvements and/or
c. This warranty does not apply to equipment
changes in this manual or in the product described
which has been altered, improperly handled, or dam-
herein at any time.
aged in any way.

The Seller is in no event liable for consequential This product could include technical inaccuracies or
damages, installation cost or other costs of any nature typographical errors.
as a result of the use of the products manufactured or
supplied by the Seller, whether used in accordance
with instructions or not.

This warranty is in lieu of all others, either expressed
PHONE NUMBERS:
or implied. No representative is authorized to assume
for the Seller any other liability in connection with
Seller's products. Sales & Service [phone]
FAX [phone]

MAILING & SHIPPING ADDRESS:

MARTI Electronics, Inc.
P.O. Box 661 1501 N. Main St.
Cleburne, Texas 76031-0661
The United States of America
Table of Contents

Introduction .................................................................................................................. 1
Specifications ................................................................................................................ 2
Unpacking and Inspection ............................................................................................. 3
Installation .................................................................................................................... 4
Electrical Connections ................................................................................................... 4
Antennas .......................................................................................................................
Operation ......................................................................................................................
Step by Step Operating Procedure .................................................................................
Theory of Operation ......................................................................................................
Tools and Test Equipment Required ..............................................................................
Block Diagram, Drawing No. 702-073 ..........................................................................
Location of Adjustments, Drawing No. 702-076 ...........................................................
Factory Test Report ......................................................................................................
Tune-Up Procedure and Adjustment ..............................................................................
Function of RPT-30 Semi-Conductors ...........................................................................

Main Frame Schematic, 702-074 ......................................................
Parts List, 702-074 .......................................................

Pre-Amp/Mixer Schematic, 800-251 ......................................................
Board Parts List, 800-251 .......................................................

Audio Board Schematic, 800-166 ......................................................
Parts List, 800-166 .......................................................

Modulator Schematic, 800-160 ......................................................
Board Parts List, 800-160 .......................................................

Multiplier Schematic, 800-163 ......................................................
Board Parts List, 800-264 .......................................................

RF Power Amp Schematic, 800-170 ......................................................
Board Parts List, 800-170 .......................................................

Output Filter Schematic, 800-250 ......................................................
Board Parts List, 800-250 .......................................................

Power Supply Schematic, 800-249 ......................................................
Board Parts List, 800-249 .......................................................

Meter Board Schematic, 800-252 ......................................................
Board Parts List, 800-252 .......................................................
This page intentionally left blank
Introduction

The Marti Model RPT-30 Transmitters are output, and power supply voltage. The solid-
designed to operate in the Remote Pick-Up state audio processing technique pioneered and
Broadcast Service as defined in Part 74, Subpart proven by Marti Electronics in thousands of re-
D, of the FCC Rules and Regulations. Refer to mote pick-up broadcast transmitters over the
“Specifications” for a listing of the available past 25 years has been applied to this model, re-
bandwidths. These transmitters, when used with sulting in the highest audio quality possible,
the recommended companion receiver, provide a consistent with transmission bandwidth and
remote broadcast link having audio quality not other factors.
approached by conventional voice communica- The RPT-30 has been designed to operate
tion radio equipment. The RPT-30 transmitter with other Marti equipment to form large com-
operates from both 115 volt, 50 - 60 Hz. AC munications systems capable of covering large
commercial power and 11 to 14 volt battery areas with broadcast-quality audio, while pro-
(NEGATIVE GROUND) supply in fixed, port- viding continuous-duty operation. The RPT-30
able, or mobile, service. Four audio input chan- finds applications in mobile repeaters, fixed
nels are provided with individual mixing gain automatic repeaters, base stations, and TSL
controls. A meter and selector switch are pro- (transmitter-to-studio data links).
vided for monitoring audio compression, RF

RPT-30 Features:
• Continuous-duty output - 45 watts at 150 MHz. - 30 watts at 450 MHz.
• Four balanced microphone mixing inputs, one switchable to balanced line level.
• Dual-Frequency capability.
• Sub-Audible Encoder.
• Internal FM Compressor-Limiter.
• Internal Noise Reduction System (2:1 Audio Compander - optional)
• Flashing LEDs indicate antenna VSWR problems and over-temperature conditions
• Illuminated VU Meter.
Model RPT-30

Remote Pick-Up Broadcast Transmitter
Specifications

Frequency Range and 140 - 180 MHz. - 45 watts
Maximum Power Output: 200 - 260 MHz. - 40 watts
280 - 340 MHz. - 35 watts
400 - 480 MHz. - 30 watts

RF Connector: SO-239

Operating Temp. Range: -10 Cº to +45 Cº

Modulation (Specify): 10KOF3E FCC Frequency Group P
25KOF3E FCC Frequency Group K, L, N2
50KOF3E FCC Frequency Group N1, R

Channels (Frequencies): Two frequencies selected by switch. Frequency separation
1.1% maximum.

Frequency Stability: Mobile: .0005%
Base: .00025% (above 400 MHz.)

Spurious Emissions: Meets FCC requirements.

Audio inputs: Four balanced microphone (150 ohms) inputs (XLR-3) with
mixing controls. One input switchable to balanced line level
at microphone #4 input and D connector on rear panel.

Modulation Control: Broadcast-quality compressor/limiter built in.

Encoding: Subaudible 27 Hz. tone encoder built in.

Metering/Indicators: Illuminated meter indicates audio compression, relative RF
output, relative supply voltage. Flashing LEDs indicate
“Antenna” (VSWR too high) and “Temp.” (over-tempera-
ture indicator).

Controls: (4) INPUT LEVEL, METER switch, ENCODE switch,
FREQUENCY switch, MONITOR jack.

Power Requirements: 120/220/240 VAC (voltage to be specified on original or-
der), 50/60 Hz
DC operation on 11 - 13.5 volt negative ground.

AC Fuse Rating: For 120 v. use 2 1/2 Amp fuse

Accessory Connector: 9-pin D connector for DC power, remote control, encode,
line level input.
Weight: Net 12.4 pounds. Domestic packed 16 pounds.
Net 5.62 kilograms. Export packed 7.62 kilograms.

Dimensions: 11.5 in. wide x 3.5 in. high x 13.3 in. deep.
(29.21 cm. wide x 8.89 cm. high x 33.78 cm. deep.)

Options available: Second crystal for dual-frequency operation, rack mounting
brackets, mobile mounting brackets, antenna switching
relay, audio companding, etc. For a complete listing see last
page of this manual.

Type Acceptance FCC ID: BEN9EZRPT30-150
Numbers (FCC Part 74): FCC ID: BEN9EZRPT30-450

DOC (Canada)
Numbers:
UNPACKING & INSPECTING

This equipment was factory tested, by local agent of carrier. A written
inspected, packed, and delivered to report of the agent's findings, with
the carrier with utmost care. Do not his signature is necessary to support
accept shipment from carrier which claim. Check your shipment against
shows damage or shortage until the the shipping papers for possible
carrier's agent endorses a statement shortage. Do not discard any packing
of the irregularity on the face of the material until all items are accounted
carrier's receipt. Without for. Small items are often thrown
documentary evidence, a claim away with packing material. Packing
cannot be filed. material should be retained until
Unpack equipment immediately equipment testing is completed. Any
upon receipt and thoroughly inspect equipment returned to the factory
for concealed damage. If damage is should be packed in original cartons,
discovered, stop further unpacking insured, and pre-paid.
and request immediate inspection
Installation

Install rack-mounted equipment in a well-ventilated, STATIONARY REMOTE INSTALLATION
well-grounded, and shielded rack cabinet. Do not locate
PROCEDURE
solid-state equipment in a rack above tube-type
equipment which produces high temperatures.
1. The transmitter is normally located near the announcer
Problems can also be avoided by locating this unit or engineer to permit access to gain controls, microphone
away from other equipment which has transformers inputs, the monitor jack, and metering.
that produce strong magnetic fields. These fields can
(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
induce hum and noise into the Marti equipment thus
(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
reducing performance. Strong radio-frequency (RF)
(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
fields should be avoided where possible. Extensive (cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
shielding and filtering have been incorporated into this (cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
equipment to permit operation in moderate RF environ- (cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
ments. All equipment racks, cabinets, etc., should be (cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
bonded together by wide copper grounding strap to (cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
ensure that all system elements are at RF ground
potential.

STATIONARY REMOTE BROADCAST
Personnel must not be near the antenna when
INSTALLATION radiating. Locate antenna as far as possible from
people and equipment susceptible to RF radiation.
The basic stationary remote installation consists of the
Do not mount antenna directly on transmitter.
RPT-30 transmitter, a 115 VAC power source, micro-
Refer to ANSI C95.1 “Limits on Non-Ionizing
phones and other audio program sources, and a portable
Radiation.”
antenna. Remotes using portable antennas inside build-
ings have very limited range (typically less than one

mile). If greater range is needed, consider locating the
2. With the RPT-30 CONTROL switch in “OFF” posi-
transmitting antenna outside the building at a height
tion, plug the transmitter into a grounded, three-prong,
necessary to provide a line-of-sight path to the receiving
115 volt, AC outlet.
antenna. This may not be practical if a great length of

coaxial cable is required. Many broadcasters are using the
WARNING
Marti mobile relay system to do remotes from inside
buildings. This system consists of the originating
THIS EQUIPMENT MUST BE OPERATED WITH
transmitter with its antenna inside the building which
A 3-PRONG, GROUNDED, 115 VOLT, AC
transmits to a “mobile relay” parked outside the building.
OUTLET RECEPTACLE!
The mobile relay consists of a Marti Model AR-10 re-
ceiver and Marti RPT series transmitter with mobile
FAILURE TO USE A PROPERLY GROUNDED
antennas installed in a vehicle. The AR-10 receiver picks OUTLET COULD RESULT IN A SAFETY HAZ-
up the encoded signal originating from the RPT series ARD OR FAULTY EQUIPMENT PERFORMANCE.
transmitter located inside the building, automatically turns IF AN EXTENSION CORD IS USED, IT
MUST BE THE THREE-WIRE GROUNDING
on the relay transmitter (on a different frequency), which
TYPE TO INSURE SAFETY.
re-transmits the program to the distant receiving antenna
at the radio station studio or transmitter site. (Mobile
relay equipment packages are available from Marti.)
DO NOT CUT OFF THE GROUND PIN OF A

3-PRONG PLUG!

Excessively long extension cords
should be avoided since the voltage
drop can degrade equipment
performance. Do not allow the RPT-30 1. Locate transmitter where vent holes on top and rear of
to get wet. Do not operate where
unit are not obstructed. Leave enough space for the mic.
personnel touching the transmitter
plug on the front panel and the accessory plug on rear of
(or its microphone, antenna, or
unit.
other connected equipment) are
standing on wet ground or concrete.
2. Hook the four mounting fasteners (in retracted posi-
3. For locations where AC power is not available, the tion in the four slots on the sides of the transmitter. See
RPT-30 can be powered from a fully charged automobile Fig. 1. (Fasteners are in Mobile Mounting Kit, 700-251)
battery. The RPT-30 draws five (5) amps at 12.6 volts
DC. Use D.C. Power Cable, Fuse and Plug, No. 586-074. 3. Mark the location of the two mounting holes in each
fastener bracket. Drill 7/64” diameter holes into the
OBSERVE POLARITY: Red wire is (+) Positive and
mounting surface at the marked places for #6 x 1/2” sheet
Black is (-) Negative.
metal screws.

4. Connect a portable antenna such as the Marti
4. Attach the mounting fasteners with the sheet metal
PAV/150, PAV-450, or YC-450 to the ANTENNA con-
screws provided. Secure the transmitter with the fasten-
nector on the back of the transmitter.
ers.

MOBILE INSTALLATION
Receiver Mounting
The RPT-30 transmitter can be installed in the vehicle
For mobile repeat using the Marti AR-10 Mobile Re-
where the controls (“OFF” - “STANDBY” - “TRANS-
peat Receiver, mount the receiver near the transmitter
MIT”) can be operated directly, or the transmitter can be
using the three fasteners supplied in Mobile Mounting
located elsewhere (in the trunk of a car or rear of a van)
Kit, 700-251.
and controlled remotely. The choice depends upon the

type of vehicle and the type of operation anticipated. The
Electrical Connections
antenna(s) are usually mounted on top of the vehicle to

provide maximum height. WARNING: This equipment is designed for NEGA-
TIVE GROUND, 12 volt vehicles only. Reverse polar-
Transmitter Mounting ity may destroy all transistors in the RPT-30!
Mobile Remote Control Mobile Repeat
Remote control of the RPT-30 transmitter requires a Mobile repeat operation is covered under STATION-
switch to control primary +12 volt DC power and a sec- ARY REMOTE BROADCAST INSTALLATION. Electrical
ond switch to control the transmit function. The primary connection is through Mobile Repeat Cable No. 585-037-
+12 volt control requirement can be met by tapping the 2. This cable is connected between the RPT-30
“Accessory” circuit of the vehicle which is controlled by transmitter and AR-10 receiver. Power is obtained by
the ignition switch. The “transmit” function can be per- connecting the fused RED wire to the vehicle
formed by installing a switch on the vehicle or by the “Accessory” +12 volt circuit controlled by the vehicle
push-to-talk switch on a microphone such as the Marti ignition switch. The electrical diagram of this cable is
MCD-70B. shown in FIG. 3.
FIG. 2. shows the electrical circuit of a mobile instal-
lation.
Mobile Antenna Installation

One or more mobile antennas are required depending
CAUTION: TOTAL CONTROL CIRCUIT RESISTANCE MUST upon the various receive and transmit frequencies and
NOT EXCEED 0.3 OHMS! whether antenna duplexing is used. Antennas are speci-
fied in the various system packages listed in the Marti
Control circuits having more than 0.3 ohms resistance literature. The installer should follow the instructions
should employ a relay with low resistance contacts lo- supplied with the mobile antennas.
cated near the transmitter.